When the roster leak first happened, I took it with a grain of salt. Mainly because of Dr. Mario and Dark Pit being separate characters, it seemed odd to me at first.
But then, when I realized Duck Hunt was on the roster, I became hopeful. I love the nonhuman/animal characters, and I could see Duck Hunt being a potential main. So the more I thought about the leak, the more I wished it to be true.
Then, I remembered what Sakurai said when Lucina was revealed. He said something along the lines of characters with even the slightest gameplay difference earn themselves their own slot on the roster. Dr. Mario was indeed slightly different from Mario in Melee, and I figured Dark Pit could have differences as well. So now I understood.
And, I also realized that the arguments about "Wario's missing a pupil" and "Mr. Game and Watch's hand is overlapping" were not true if you looked closely.
And at last, Shulk's reveal. The fact that his artwork matched up to the leak basically proved it (as if the leaked Bowser Jr. videos being taken down wasn't enough). Meaning Duck Hunt was real.
And the game coming out in Japan proved it even further with gameplay videos of the newcomers. Such as Duck Hunt.
Overall, I was really happy when the leak was shown to be true, simply because of Duck Hunt (and also Bowser Jr. plus the Koopaling alts, but that's another story). And when we got to see Duck Hunt's alts, I was pleasantly surprised as well.
So to sum it all up, Duck Hunt = YES YES YES YES! Even though I never played the game, I really liked the idea. (Maybe not playing the game is a good thing, though, since a large number of people who have played it hate the dog and his laugh...)